Journal of Interdisciplinary Science Topics
Slapping Someone Into Next Week
James Pierce, Jon Cogle, Jake Cox
The Centre for Interdisciplinary Science, University of Leicester
01/02/2013
Abstract
This paper exams the science behind the phrase ‘Slapping someone into next week’ and provides an estimate of
the conditions necessary and feasibility of performing such an act.
Introduction
The threat of ‘slapping someone into next week’ is
well used in popular culture in both film and
television. Used as a way of threatening someone
with a strike of such force as to bend the laws of
Physics. However we investigate whether such a feat
of strength could be possible and what conditions
would be needed.
We provide an answer to this problem by
considering Einstein’s theory of special relativity.
One of the postulates of this theory is that the laws
which govern physical systems are measured and
perceived equally for two systems at rest relative to
each other1. When two systems are moving at
different velocities to each other, they observe
differences in measurements between themselves
and the other system.
This postulate can be applied to our problem, if we
consider the attacker and the victim as our two
systems, the attacker needs to impart such a
velocity to the victim that they experience one week
of time relative to the attacker. The difference
between the observed passage of time for both
people is known as a Lorentz Transformation2.
Theory
There are various steps in the calculations to solve
this problem, the main two which concern the
Lorentz Transformations are to find the ratio
between the two observed time changes and to
determine at what the victim would have to be
moving relative to the attacker. The ratio of the
measured times is known as the Gamma Factor and
is given by3:
Once we have this value we find the relative velocity
v which would cause this gamma factor. This is
found using3:
Finding the necessary force required to accelerate a
person to that speed is found by first finding the
acceleration caused by this velocity:
Rearranged assuming initial velocity of 0:
This value for a is then put into Newton’s second law
to find the force imparted onto the victim:
These equations are then run back to find the
velocity that the hand must be travelling in order to
create such a force.
A number of reasonable assumptions are made to
provide an answer to the question:
 The victim experiences 6.05×105seconds (1
week) to the attacker’s 1 second.
Slapped into next week, February 1st 2013


Both people weigh 80kg and the attackers
hand weighs 500g.
That the victim’s body is resistant to the
enormous forces and accelerations involved.
Conclusion
From the values we assumed, we found that the
victim would have to be travelling at 99.9% the
speed of light. In order to convey that kind of speed
to them, the attackers hand would have to be
travelling in the order of hundreds of times the
speed of light, 5.31×1010ms-1 to be precise. This
value is clearly beyond the realms of possibility as
the speed of light is considered a universal speed
limit.
Realistically, assuming even the fastest punch were
to land, the victim is unlikely to travel through any
real difference in time in relation to the attacker. We
re-calculated the time difference with a more
realistic striking velocity of 10ms-1. Applying this
realistic value, the difference in time is in the order
of 10-18- 10-21seconds. This report would therefore
suggest a more apt and accurate phrase, following
real world calculations to be, “I’m going to slap you
into the next femto second”.
References
[1] http://www.fourmilab.ch/etexts/einstein/specrel/www/
[2] http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/ltrans.html
[3] Tipler, P.A. & Mosca, G. (2008) Physics For Scientists and Engineers, 6th Ed. Freeman